The Evolution of Endodontics
Advancements in endodontic techniques have helped both the efficacy and efficiency of this critical treatment modality.
Endodontic therapy has evolved greatly over the past two decades. Years of stagnant growth in what appeared to be a fully mature, long, and tedious operating procedure for the treatment of endodontic disease was suddenly upended with the rapid introduction of several key technologies within a few short years that helped revolutionize the field. These technological advancements included, but were not limited to, the advent of nickel-titanium rotary files, piezo-electric ultrasonics, apex locators, bioceramic obturation and root repair materials, and the use of the surgical operating microscopes.
The synergistic use of these and other technologies, along with an improved understanding of the scientific concepts behind the field—particularly related to irrigation and disinfection—helped propel endodontic therapy into a new direction and changed the traditional techniques of blind cleaning and shaping procedure done by hand instrumentation over the course of multiple and often painful visits to a single-visit procedure based on excellent visualization and exploration of the canals under strict aseptic protocol with the aid of nickel-titanium instrumentation and copious irrigation.
And, now the procedure could be performed completely painlessly. As the crucial concept of canal disinfection through effective irrigation in the depth of the canal became clear, more efficient irrigation techniques that allowed the passage of a large volume of irrigant deep into the canal helped make deep disinfection safe and efficient.
Although some would argue that these technological advancements have only improved the efficiency of care and not its quality, this author would like to remind those folks that as far as most patients are concerned, improving the efficiency of care is itself an improvement in the quality of care. Because efficiency and quality are not mutually exclusive, as long as the quality of care does not drop by the gained speed we have improved a technique by making it more efficient for the patient. And if we survey dental patients requiring root canal therapy, we can assume that they agree that as long as the quality of the treatment is not compromised, an improvement in efficiency helps to make the procedure more appealing to them. Dental patients benefit from more efficient procedures in the same way consumers benefited from a more efficient shopping experience after the advent of barcode technology.
However, the argument that only efficiency and not quality has been improved seems intuitively wrong to any clinicians who is proficient in the use of the operating microscope (Figure 1 and Figure 2). These clinicians will attest that modern endodontic therapy performed under the operating microscope feels like an entirely different procedural concept than its old counterpart, which was performed by the naked eye. Nowhere else is the benefit of this technological advancement more felt than during surgical apicoectomies. The surgical operating microscope alone has revived the apicoectomy procedure from the brink of extinction. Recent clinical prospective studies have shown the much higher success rates enjoyed by the clinician who combine sound microsurgical techniques with wise case selection and meticulous surgical protocol.1
While advancement in instrument technology has driven the field over past two decades, the next few years appear to be led by advancements in material science and improved clinical concepts. The application and incorporation of more modern biomaterials such as bioceramics in root canal sealers and root repair materials seems to be the next step in biomaterials entering the endodontic scene. More research in this area is under way, but so far, bioceramic-based materials appear very promising when it comes to fulfilling Grossman's criteria of an ideal endodontic cement.2
Our conceptual understanding of the criteria for success is also evolving. Competing procedures defining success as mere survival, such as extraction and replacement with an implant, have actually helped endodontics to be more results-oriented, and this will undoubtedly improve success rates of this great procedure. A recent, large-scale epidemiological study at the University of Southern California showed an 8-year survival rate associated with endodontic therapy that exceeded 97%.3 This is significantly higher than implant procedures because the endodontic survival study was all-inclusive and did not select a specific group of healthy individuals and omit patients from the study based on medical status or other factors such as bruxism.
On a different front, endodontic irrigation is finally at center stage as one of the most significant factors for improving success rates. Negative pressure irrigation systems are helping clinicians achieve unprecedented levels of deep canal irrigation.4 Obviously, the use of illumination and magnification, as well as redefining correct access preparations, is helping to improve chamber exploration and hopefully reduce the incidence of missed root canals.5 Meanwhile, missed root canals remain the number one cause of endodontic failure. The MB2 in maxillary molars, disto–lingual or disto–buccal in mandibular molars, one or more additional canals in premolars, and the lingual canal in lower incisors are now accepted as norms that should be explored routinely, not as anatomical exceptions.6 This recognition compels all clinicians to step up their exploration under magnification and illumination to improve their success rates.
Furthermore, it appears that some people in the field are now questioning the idea of any successful root canal procedure being a technically complex and technologically challenging feat. The "razzle-dazzle" of complicated endodontics seems to have given birth to a new era of simplicity. This, however, does not make the endodontic procedure simple. It only indicates that clinicians better understand now the importance of a few significant, yet simple clinical concepts such as complete asepsis, identification of all root canals, disinfection of all canals to the apex, and those canals' obturation with a relatively simple, conservative obturation technique as basic criteria for success. However, the devil is in the details and endodontic therapy remains a procedure based on a few simple concepts and a large volume of details. During the process of deciphering the dos and the don'ts during daily procedures, clinicians must constantly balance their personal need for implementing specific and idealistic criteria for success vs. the patient's needs of a quality treatment that lasts for as long as possible. Sacrificing important root structure for the sake of achieving a certain "look" in the radiograph does not help to improve the success rate but may instead compromise the tooth's biomechanics and weaken the root. Conservative treatment and preservation of natural tooth structure usually proves to be a better choice in the long run.
Finally, while the long-term direction and goal of the endodontic field remains the prevention of disease and regeneration of the pulp and the tooth organ, we are still committed to improving our repair procedures by improving the root canal procedure and techniques related to enhancing success and patient comfort. Astute clinicians use technology within the framework of sound scientific concepts that are based on improving quality, efficiency, while only emphasizing those aspects of care that improve patient care and optimize clinical success in the long run.
1. Rubinstein R, Kim S. Long-term follow-up of cases considered healed one year after apical microsurgery. J Endod. 2002;28(5):378-383.
2. Grossman L. Obturation of root canal. In: Grossman L, ed. Endodontic Practice. 10th ed. Philadelphia, PA: Lea and Febiger; 1982:297.
3. Salehrabi R, Rotstein I. Endodontic treatment outcomes in a large patient population in the USA: An epidemiologic study. J Endod. 2004;30:846-850.
4. Nielsen BA, Baumgartner CJ. Comparison of the EndoVac System to needle irrigation of root canals. J Endod. 2007;33(5)611-615.
5. Carr GB. Advanced techniques and visual enhancement for endodontic surgery. Endod Rep. 1992;7(1):6-9.
6. de Carvalho MC, Zuolo ML. Orifice locating with a microscope. J Endod. 2000;26(9):532-534.
About the Author
Allen Ali Nasseh, DDS, MMSc
Department of Restorative Dentistry and Biomaterial Sciences
Harvard University School of Dental Medicine